A magnetostriction phenomenon is a phenomenon in which a magnetic body is deformed by a magnetic field applied externally. A magnetostrictive material exhibiting the magnetostriction phenomenon is subjected to deformation in a state of an external magnetic field being applied thereto, and thereby magnetization inside the magnetostrictive material changes. This phenomenon is called an inverse magnetostriction phenomenon or a Villari effect. A power generating device using the inverse magnetostriction phenomenon has been proposed (see Non-Patent Documents 1 and 2, for example).    Non-Patent Document 1: Shonan-metaltec Corporation, “Introduction of inverse magnetostriction type vibration power generator of SMT development,” [online], [search on Nov. 8, 2011] Internet <URL: http://www.shonan-metaltec.com/HPdata/info_gyakujiwai_hatudenki.pdf>    Non-Patent Document 2: UENO, Toshiyuki, “Micro energy harvesting device using magnetostrictive material,” [online], Aug. 6, 2010, Kanazawa University New Technology Presentation Meetings [search on Nov. 8, 2011] Internet <URL: http://jstshingi.jp/abst/p/10/1022/kanazawa1.pdf>